Inductive powering of an intermittently energized device would be extremely convenient. A primary is provided at some convenient location. When placed in proximity to the primary, a device with a suitable secondary is energized without the need to connect a cord or cable to the device. However, with an inductive power supply, such rapid changing of power consumption is problematic.
Certain devices, such as those used for cooking, are designed to intermittently derive power from a power source. For example, an electric skillet uses significant power to heat its cooking surface to a desired temperature. When it reaches that temperature, the skillet ceases using power. If the cooking surface cools, it again uses significant power to heat the cooking surface.
An inductive power supply establishes a magnetic field from which the remote device draws power. The instantaneous cessation of power consumption by the remote device does not automatically end the magnetic field. Rather, the magnetic field previously established may continue to exist after the remote device is no longer drawing power. The inductive power supply could continue to supply power to the magnetic field, resulting in excessive currents within the power supply. If left unchecked, these large currents in the power supply can ultimately result in the destruction of the electronic components of the power supply, such as transistors and other semiconductor devices, rendering the power supply unusable.
An improved inductive circuit for powering a load is thus highly desirable.